1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Implementation of the Transmission Control Protocol(TCP). 7 * 8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $ 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * Mark Evans, <evansmp@uhura.aston.ac.uk> 13 * Corey Minyard <wf-rch!minyard@relay.EU.net> 14 * Florian La Roche, <flla@stud.uni-sb.de> 15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> 16 * Linus Torvalds, <torvalds@cs.helsinki.fi> 17 * Alan Cox, <gw4pts@gw4pts.ampr.org> 18 * Matthew Dillon, <dillon@apollo.west.oic.com> 19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 20 * Jorge Cwik, <jorge@laser.satlink.net> 21 * 22 * Fixes: 23 * Alan Cox : Numerous verify_area() calls 24 * Alan Cox : Set the ACK bit on a reset 25 * Alan Cox : Stopped it crashing if it closed while 26 * sk->inuse=1 and was trying to connect 27 * (tcp_err()). 28 * Alan Cox : All icmp error handling was broken 29 * pointers passed where wrong and the 30 * socket was looked up backwards. Nobody 31 * tested any icmp error code obviously. 32 * Alan Cox : tcp_err() now handled properly. It 33 * wakes people on errors. poll 34 * behaves and the icmp error race 35 * has gone by moving it into sock.c 36 * Alan Cox : tcp_send_reset() fixed to work for 37 * everything not just packets for 38 * unknown sockets. 39 * Alan Cox : tcp option processing. 40 * Alan Cox : Reset tweaked (still not 100%) [Had 41 * syn rule wrong] 42 * Herp Rosmanith : More reset fixes 43 * Alan Cox : No longer acks invalid rst frames. 44 * Acking any kind of RST is right out. 45 * Alan Cox : Sets an ignore me flag on an rst 46 * receive otherwise odd bits of prattle 47 * escape still 48 * Alan Cox : Fixed another acking RST frame bug. 49 * Should stop LAN workplace lockups. 50 * Alan Cox : Some tidyups using the new skb list 51 * facilities 52 * Alan Cox : sk->keepopen now seems to work 53 * Alan Cox : Pulls options out correctly on accepts 54 * Alan Cox : Fixed assorted sk->rqueue->next errors 55 * Alan Cox : PSH doesn't end a TCP read. Switched a 56 * bit to skb ops. 57 * Alan Cox : Tidied tcp_data to avoid a potential 58 * nasty. 59 * Alan Cox : Added some better commenting, as the 60 * tcp is hard to follow 61 * Alan Cox : Removed incorrect check for 20 * psh 62 * Michael O'Reilly : ack < copied bug fix. 63 * Johannes Stille : Misc tcp fixes (not all in yet). 64 * Alan Cox : FIN with no memory -> CRASH 65 * Alan Cox : Added socket option proto entries. 66 * Also added awareness of them to accept. 67 * Alan Cox : Added TCP options (SOL_TCP) 68 * Alan Cox : Switched wakeup calls to callbacks, 69 * so the kernel can layer network 70 * sockets. 71 * Alan Cox : Use ip_tos/ip_ttl settings. 72 * Alan Cox : Handle FIN (more) properly (we hope). 73 * Alan Cox : RST frames sent on unsynchronised 74 * state ack error. 75 * Alan Cox : Put in missing check for SYN bit. 76 * Alan Cox : Added tcp_select_window() aka NET2E 77 * window non shrink trick. 78 * Alan Cox : Added a couple of small NET2E timer 79 * fixes 80 * Charles Hedrick : TCP fixes 81 * Toomas Tamm : TCP window fixes 82 * Alan Cox : Small URG fix to rlogin ^C ack fight 83 * Charles Hedrick : Rewrote most of it to actually work 84 * Linus : Rewrote tcp_read() and URG handling 85 * completely 86 * Gerhard Koerting: Fixed some missing timer handling 87 * Matthew Dillon : Reworked TCP machine states as per RFC 88 * Gerhard Koerting: PC/TCP workarounds 89 * Adam Caldwell : Assorted timer/timing errors 90 * Matthew Dillon : Fixed another RST bug 91 * Alan Cox : Move to kernel side addressing changes. 92 * Alan Cox : Beginning work on TCP fastpathing 93 * (not yet usable) 94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine. 95 * Alan Cox : TCP fast path debugging 96 * Alan Cox : Window clamping 97 * Michael Riepe : Bug in tcp_check() 98 * Matt Dillon : More TCP improvements and RST bug fixes 99 * Matt Dillon : Yet more small nasties remove from the 100 * TCP code (Be very nice to this man if 101 * tcp finally works 100%) 8) 102 * Alan Cox : BSD accept semantics. 103 * Alan Cox : Reset on closedown bug. 104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto(). 105 * Michael Pall : Handle poll() after URG properly in 106 * all cases. 107 * Michael Pall : Undo the last fix in tcp_read_urg() 108 * (multi URG PUSH broke rlogin). 109 * Michael Pall : Fix the multi URG PUSH problem in 110 * tcp_readable(), poll() after URG 111 * works now. 112 * Michael Pall : recv(...,MSG_OOB) never blocks in the 113 * BSD api. 114 * Alan Cox : Changed the semantics of sk->socket to 115 * fix a race and a signal problem with 116 * accept() and async I/O. 117 * Alan Cox : Relaxed the rules on tcp_sendto(). 118 * Yury Shevchuk : Really fixed accept() blocking problem. 119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for 120 * clients/servers which listen in on 121 * fixed ports. 122 * Alan Cox : Cleaned the above up and shrank it to 123 * a sensible code size. 124 * Alan Cox : Self connect lockup fix. 125 * Alan Cox : No connect to multicast. 126 * Ross Biro : Close unaccepted children on master 127 * socket close. 128 * Alan Cox : Reset tracing code. 129 * Alan Cox : Spurious resets on shutdown. 130 * Alan Cox : Giant 15 minute/60 second timer error 131 * Alan Cox : Small whoops in polling before an 132 * accept. 133 * Alan Cox : Kept the state trace facility since 134 * it's handy for debugging. 135 * Alan Cox : More reset handler fixes. 136 * Alan Cox : Started rewriting the code based on 137 * the RFC's for other useful protocol 138 * references see: Comer, KA9Q NOS, and 139 * for a reference on the difference 140 * between specifications and how BSD 141 * works see the 4.4lite source. 142 * A.N.Kuznetsov : Don't time wait on completion of tidy 143 * close. 144 * Linus Torvalds : Fin/Shutdown & copied_seq changes. 145 * Linus Torvalds : Fixed BSD port reuse to work first syn 146 * Alan Cox : Reimplemented timers as per the RFC 147 * and using multiple timers for sanity. 148 * Alan Cox : Small bug fixes, and a lot of new 149 * comments. 150 * Alan Cox : Fixed dual reader crash by locking 151 * the buffers (much like datagram.c) 152 * Alan Cox : Fixed stuck sockets in probe. A probe 153 * now gets fed up of retrying without 154 * (even a no space) answer. 155 * Alan Cox : Extracted closing code better 156 * Alan Cox : Fixed the closing state machine to 157 * resemble the RFC. 158 * Alan Cox : More 'per spec' fixes. 159 * Jorge Cwik : Even faster checksumming. 160 * Alan Cox : tcp_data() doesn't ack illegal PSH 161 * only frames. At least one pc tcp stack 162 * generates them. 163 * Alan Cox : Cache last socket. 164 * Alan Cox : Per route irtt. 165 * Matt Day : poll()->select() match BSD precisely on error 166 * Alan Cox : New buffers 167 * Marc Tamsky : Various sk->prot->retransmits and 168 * sk->retransmits misupdating fixed. 169 * Fixed tcp_write_timeout: stuck close, 170 * and TCP syn retries gets used now. 171 * Mark Yarvis : In tcp_read_wakeup(), don't send an 172 * ack if state is TCP_CLOSED. 173 * Alan Cox : Look up device on a retransmit - routes may 174 * change. Doesn't yet cope with MSS shrink right 175 * but it's a start! 176 * Marc Tamsky : Closing in closing fixes. 177 * Mike Shaver : RFC1122 verifications. 178 * Alan Cox : rcv_saddr errors. 179 * Alan Cox : Block double connect(). 180 * Alan Cox : Small hooks for enSKIP. 181 * Alexey Kuznetsov: Path MTU discovery. 182 * Alan Cox : Support soft errors. 183 * Alan Cox : Fix MTU discovery pathological case 184 * when the remote claims no mtu! 185 * Marc Tamsky : TCP_CLOSE fix. 186 * Colin (G3TNE) : Send a reset on syn ack replies in 187 * window but wrong (fixes NT lpd problems) 188 * Pedro Roque : Better TCP window handling, delayed ack. 189 * Joerg Reuter : No modification of locked buffers in 190 * tcp_do_retransmit() 191 * Eric Schenk : Changed receiver side silly window 192 * avoidance algorithm to BSD style 193 * algorithm. This doubles throughput 194 * against machines running Solaris, 195 * and seems to result in general 196 * improvement. 197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD 198 * Willy Konynenberg : Transparent proxying support. 199 * Mike McLagan : Routing by source 200 * Keith Owens : Do proper merging with partial SKB's in 201 * tcp_do_sendmsg to avoid burstiness. 202 * Eric Schenk : Fix fast close down bug with 203 * shutdown() followed by close(). 204 * Andi Kleen : Make poll agree with SIGIO 205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and 206 * lingertime == 0 (RFC 793 ABORT Call) 207 * Hirokazu Takahashi : Use copy_from_user() instead of 208 * csum_and_copy_from_user() if possible. 209 * 210 * This program is free software; you can redistribute it and/or 211 * modify it under the terms of the GNU General Public License 212 * as published by the Free Software Foundation; either version 213 * 2 of the License, or(at your option) any later version. 214 * 215 * Description of States: 216 * 217 * TCP_SYN_SENT sent a connection request, waiting for ack 218 * 219 * TCP_SYN_RECV received a connection request, sent ack, 220 * waiting for final ack in three-way handshake. 221 * 222 * TCP_ESTABLISHED connection established 223 * 224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete 225 * transmission of remaining buffered data 226 * 227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote 228 * to shutdown 229 * 230 * TCP_CLOSING both sides have shutdown but we still have 231 * data we have to finish sending 232 * 233 * TCP_TIME_WAIT timeout to catch resent junk before entering 234 * closed, can only be entered from FIN_WAIT2 235 * or CLOSING. Required because the other end 236 * may not have gotten our last ACK causing it 237 * to retransmit the data packet (which we ignore) 238 * 239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for 240 * us to finish writing our data and to shutdown 241 * (we have to close() to move on to LAST_ACK) 242 * 243 * TCP_LAST_ACK out side has shutdown after remote has 244 * shutdown. There may still be data in our 245 * buffer that we have to finish sending 246 * 247 * TCP_CLOSE socket is finished 248 */ 249 250 #include <linux/module.h> 251 #include <linux/types.h> 252 #include <linux/fcntl.h> 253 #include <linux/poll.h> 254 #include <linux/init.h> 255 #include <linux/fs.h> 256 #include <linux/random.h> 257 #include <linux/bootmem.h> 258 #include <linux/cache.h> 259 #include <linux/err.h> 260 #include <linux/crypto.h> 261 262 #include <net/icmp.h> 263 #include <net/tcp.h> 264 #include <net/xfrm.h> 265 #include <net/ip.h> 266 #include <net/netdma.h> 267 268 #include <asm/uaccess.h> 269 #include <asm/ioctls.h> 270 271 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 272 273 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly; 274 275 atomic_t tcp_orphan_count = ATOMIC_INIT(0); 276 277 EXPORT_SYMBOL_GPL(tcp_orphan_count); 278 279 int sysctl_tcp_mem[3] __read_mostly; 280 int sysctl_tcp_wmem[3] __read_mostly; 281 int sysctl_tcp_rmem[3] __read_mostly; 282 283 EXPORT_SYMBOL(sysctl_tcp_mem); 284 EXPORT_SYMBOL(sysctl_tcp_rmem); 285 EXPORT_SYMBOL(sysctl_tcp_wmem); 286 287 atomic_t tcp_memory_allocated; /* Current allocated memory. */ 288 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */ 289 290 EXPORT_SYMBOL(tcp_memory_allocated); 291 EXPORT_SYMBOL(tcp_sockets_allocated); 292 293 /* 294 * Pressure flag: try to collapse. 295 * Technical note: it is used by multiple contexts non atomically. 296 * All the sk_stream_mem_schedule() is of this nature: accounting 297 * is strict, actions are advisory and have some latency. 298 */ 299 int tcp_memory_pressure __read_mostly; 300 301 EXPORT_SYMBOL(tcp_memory_pressure); 302 303 void tcp_enter_memory_pressure(void) 304 { 305 if (!tcp_memory_pressure) { 306 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES); 307 tcp_memory_pressure = 1; 308 } 309 } 310 311 EXPORT_SYMBOL(tcp_enter_memory_pressure); 312 313 /* 314 * Wait for a TCP event. 315 * 316 * Note that we don't need to lock the socket, as the upper poll layers 317 * take care of normal races (between the test and the event) and we don't 318 * go look at any of the socket buffers directly. 319 */ 320 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 321 { 322 unsigned int mask; 323 struct sock *sk = sock->sk; 324 struct tcp_sock *tp = tcp_sk(sk); 325 326 poll_wait(file, sk->sk_sleep, wait); 327 if (sk->sk_state == TCP_LISTEN) 328 return inet_csk_listen_poll(sk); 329 330 /* Socket is not locked. We are protected from async events 331 by poll logic and correct handling of state changes 332 made by another threads is impossible in any case. 333 */ 334 335 mask = 0; 336 if (sk->sk_err) 337 mask = POLLERR; 338 339 /* 340 * POLLHUP is certainly not done right. But poll() doesn't 341 * have a notion of HUP in just one direction, and for a 342 * socket the read side is more interesting. 343 * 344 * Some poll() documentation says that POLLHUP is incompatible 345 * with the POLLOUT/POLLWR flags, so somebody should check this 346 * all. But careful, it tends to be safer to return too many 347 * bits than too few, and you can easily break real applications 348 * if you don't tell them that something has hung up! 349 * 350 * Check-me. 351 * 352 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 353 * our fs/select.c). It means that after we received EOF, 354 * poll always returns immediately, making impossible poll() on write() 355 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 356 * if and only if shutdown has been made in both directions. 357 * Actually, it is interesting to look how Solaris and DUX 358 * solve this dilemma. I would prefer, if PULLHUP were maskable, 359 * then we could set it on SND_SHUTDOWN. BTW examples given 360 * in Stevens' books assume exactly this behaviour, it explains 361 * why PULLHUP is incompatible with POLLOUT. --ANK 362 * 363 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 364 * blocking on fresh not-connected or disconnected socket. --ANK 365 */ 366 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 367 mask |= POLLHUP; 368 if (sk->sk_shutdown & RCV_SHUTDOWN) 369 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 370 371 /* Connected? */ 372 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { 373 /* Potential race condition. If read of tp below will 374 * escape above sk->sk_state, we can be illegally awaken 375 * in SYN_* states. */ 376 if ((tp->rcv_nxt != tp->copied_seq) && 377 (tp->urg_seq != tp->copied_seq || 378 tp->rcv_nxt != tp->copied_seq + 1 || 379 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data)) 380 mask |= POLLIN | POLLRDNORM; 381 382 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 383 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 384 mask |= POLLOUT | POLLWRNORM; 385 } else { /* send SIGIO later */ 386 set_bit(SOCK_ASYNC_NOSPACE, 387 &sk->sk_socket->flags); 388 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 389 390 /* Race breaker. If space is freed after 391 * wspace test but before the flags are set, 392 * IO signal will be lost. 393 */ 394 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 395 mask |= POLLOUT | POLLWRNORM; 396 } 397 } 398 399 if (tp->urg_data & TCP_URG_VALID) 400 mask |= POLLPRI; 401 } 402 return mask; 403 } 404 405 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 406 { 407 struct tcp_sock *tp = tcp_sk(sk); 408 int answ; 409 410 switch (cmd) { 411 case SIOCINQ: 412 if (sk->sk_state == TCP_LISTEN) 413 return -EINVAL; 414 415 lock_sock(sk); 416 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 417 answ = 0; 418 else if (sock_flag(sk, SOCK_URGINLINE) || 419 !tp->urg_data || 420 before(tp->urg_seq, tp->copied_seq) || 421 !before(tp->urg_seq, tp->rcv_nxt)) { 422 answ = tp->rcv_nxt - tp->copied_seq; 423 424 /* Subtract 1, if FIN is in queue. */ 425 if (answ && !skb_queue_empty(&sk->sk_receive_queue)) 426 answ -= 427 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin; 428 } else 429 answ = tp->urg_seq - tp->copied_seq; 430 release_sock(sk); 431 break; 432 case SIOCATMARK: 433 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 434 break; 435 case SIOCOUTQ: 436 if (sk->sk_state == TCP_LISTEN) 437 return -EINVAL; 438 439 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 440 answ = 0; 441 else 442 answ = tp->write_seq - tp->snd_una; 443 break; 444 default: 445 return -ENOIOCTLCMD; 446 } 447 448 return put_user(answ, (int __user *)arg); 449 } 450 451 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 452 { 453 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH; 454 tp->pushed_seq = tp->write_seq; 455 } 456 457 static inline int forced_push(struct tcp_sock *tp) 458 { 459 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 460 } 461 462 static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 463 { 464 struct tcp_sock *tp = tcp_sk(sk); 465 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 466 467 skb->csum = 0; 468 tcb->seq = tcb->end_seq = tp->write_seq; 469 tcb->flags = TCPCB_FLAG_ACK; 470 tcb->sacked = 0; 471 skb_header_release(skb); 472 tcp_add_write_queue_tail(sk, skb); 473 sk_charge_skb(sk, skb); 474 if (tp->nonagle & TCP_NAGLE_PUSH) 475 tp->nonagle &= ~TCP_NAGLE_PUSH; 476 } 477 478 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags, 479 struct sk_buff *skb) 480 { 481 if (flags & MSG_OOB) { 482 tp->urg_mode = 1; 483 tp->snd_up = tp->write_seq; 484 TCP_SKB_CB(skb)->sacked |= TCPCB_URG; 485 } 486 } 487 488 static inline void tcp_push(struct sock *sk, int flags, int mss_now, 489 int nonagle) 490 { 491 struct tcp_sock *tp = tcp_sk(sk); 492 493 if (tcp_send_head(sk)) { 494 struct sk_buff *skb = tcp_write_queue_tail(sk); 495 if (!(flags & MSG_MORE) || forced_push(tp)) 496 tcp_mark_push(tp, skb); 497 tcp_mark_urg(tp, flags, skb); 498 __tcp_push_pending_frames(sk, mss_now, 499 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 500 } 501 } 502 503 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, 504 size_t psize, int flags) 505 { 506 struct tcp_sock *tp = tcp_sk(sk); 507 int mss_now, size_goal; 508 int err; 509 ssize_t copied; 510 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 511 512 /* Wait for a connection to finish. */ 513 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 514 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 515 goto out_err; 516 517 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 518 519 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 520 size_goal = tp->xmit_size_goal; 521 copied = 0; 522 523 err = -EPIPE; 524 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 525 goto do_error; 526 527 while (psize > 0) { 528 struct sk_buff *skb = tcp_write_queue_tail(sk); 529 struct page *page = pages[poffset / PAGE_SIZE]; 530 int copy, i, can_coalesce; 531 int offset = poffset % PAGE_SIZE; 532 int size = min_t(size_t, psize, PAGE_SIZE - offset); 533 534 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 535 new_segment: 536 if (!sk_stream_memory_free(sk)) 537 goto wait_for_sndbuf; 538 539 skb = sk_stream_alloc_pskb(sk, 0, 0, 540 sk->sk_allocation); 541 if (!skb) 542 goto wait_for_memory; 543 544 skb_entail(sk, skb); 545 copy = size_goal; 546 } 547 548 if (copy > size) 549 copy = size; 550 551 i = skb_shinfo(skb)->nr_frags; 552 can_coalesce = skb_can_coalesce(skb, i, page, offset); 553 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 554 tcp_mark_push(tp, skb); 555 goto new_segment; 556 } 557 if (!sk_stream_wmem_schedule(sk, copy)) 558 goto wait_for_memory; 559 560 if (can_coalesce) { 561 skb_shinfo(skb)->frags[i - 1].size += copy; 562 } else { 563 get_page(page); 564 skb_fill_page_desc(skb, i, page, offset, copy); 565 } 566 567 skb->len += copy; 568 skb->data_len += copy; 569 skb->truesize += copy; 570 sk->sk_wmem_queued += copy; 571 sk->sk_forward_alloc -= copy; 572 skb->ip_summed = CHECKSUM_PARTIAL; 573 tp->write_seq += copy; 574 TCP_SKB_CB(skb)->end_seq += copy; 575 skb_shinfo(skb)->gso_segs = 0; 576 577 if (!copied) 578 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 579 580 copied += copy; 581 poffset += copy; 582 if (!(psize -= copy)) 583 goto out; 584 585 if (skb->len < mss_now || (flags & MSG_OOB)) 586 continue; 587 588 if (forced_push(tp)) { 589 tcp_mark_push(tp, skb); 590 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 591 } else if (skb == tcp_send_head(sk)) 592 tcp_push_one(sk, mss_now); 593 continue; 594 595 wait_for_sndbuf: 596 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 597 wait_for_memory: 598 if (copied) 599 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 600 601 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 602 goto do_error; 603 604 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 605 size_goal = tp->xmit_size_goal; 606 } 607 608 out: 609 if (copied) 610 tcp_push(sk, flags, mss_now, tp->nonagle); 611 return copied; 612 613 do_error: 614 if (copied) 615 goto out; 616 out_err: 617 return sk_stream_error(sk, flags, err); 618 } 619 620 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, 621 size_t size, int flags) 622 { 623 ssize_t res; 624 struct sock *sk = sock->sk; 625 626 if (!(sk->sk_route_caps & NETIF_F_SG) || 627 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 628 return sock_no_sendpage(sock, page, offset, size, flags); 629 630 lock_sock(sk); 631 TCP_CHECK_TIMER(sk); 632 res = do_tcp_sendpages(sk, &page, offset, size, flags); 633 TCP_CHECK_TIMER(sk); 634 release_sock(sk); 635 return res; 636 } 637 638 #define TCP_PAGE(sk) (sk->sk_sndmsg_page) 639 #define TCP_OFF(sk) (sk->sk_sndmsg_off) 640 641 static inline int select_size(struct sock *sk) 642 { 643 struct tcp_sock *tp = tcp_sk(sk); 644 int tmp = tp->mss_cache; 645 646 if (sk->sk_route_caps & NETIF_F_SG) { 647 if (sk_can_gso(sk)) 648 tmp = 0; 649 else { 650 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 651 652 if (tmp >= pgbreak && 653 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 654 tmp = pgbreak; 655 } 656 } 657 658 return tmp; 659 } 660 661 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 662 size_t size) 663 { 664 struct iovec *iov; 665 struct tcp_sock *tp = tcp_sk(sk); 666 struct sk_buff *skb; 667 int iovlen, flags; 668 int mss_now, size_goal; 669 int err, copied; 670 long timeo; 671 672 lock_sock(sk); 673 TCP_CHECK_TIMER(sk); 674 675 flags = msg->msg_flags; 676 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 677 678 /* Wait for a connection to finish. */ 679 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 680 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 681 goto out_err; 682 683 /* This should be in poll */ 684 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 685 686 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 687 size_goal = tp->xmit_size_goal; 688 689 /* Ok commence sending. */ 690 iovlen = msg->msg_iovlen; 691 iov = msg->msg_iov; 692 copied = 0; 693 694 err = -EPIPE; 695 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 696 goto do_error; 697 698 while (--iovlen >= 0) { 699 int seglen = iov->iov_len; 700 unsigned char __user *from = iov->iov_base; 701 702 iov++; 703 704 while (seglen > 0) { 705 int copy; 706 707 skb = tcp_write_queue_tail(sk); 708 709 if (!tcp_send_head(sk) || 710 (copy = size_goal - skb->len) <= 0) { 711 712 new_segment: 713 /* Allocate new segment. If the interface is SG, 714 * allocate skb fitting to single page. 715 */ 716 if (!sk_stream_memory_free(sk)) 717 goto wait_for_sndbuf; 718 719 skb = sk_stream_alloc_pskb(sk, select_size(sk), 720 0, sk->sk_allocation); 721 if (!skb) 722 goto wait_for_memory; 723 724 /* 725 * Check whether we can use HW checksum. 726 */ 727 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 728 skb->ip_summed = CHECKSUM_PARTIAL; 729 730 skb_entail(sk, skb); 731 copy = size_goal; 732 } 733 734 /* Try to append data to the end of skb. */ 735 if (copy > seglen) 736 copy = seglen; 737 738 /* Where to copy to? */ 739 if (skb_tailroom(skb) > 0) { 740 /* We have some space in skb head. Superb! */ 741 if (copy > skb_tailroom(skb)) 742 copy = skb_tailroom(skb); 743 if ((err = skb_add_data(skb, from, copy)) != 0) 744 goto do_fault; 745 } else { 746 int merge = 0; 747 int i = skb_shinfo(skb)->nr_frags; 748 struct page *page = TCP_PAGE(sk); 749 int off = TCP_OFF(sk); 750 751 if (skb_can_coalesce(skb, i, page, off) && 752 off != PAGE_SIZE) { 753 /* We can extend the last page 754 * fragment. */ 755 merge = 1; 756 } else if (i == MAX_SKB_FRAGS || 757 (!i && 758 !(sk->sk_route_caps & NETIF_F_SG))) { 759 /* Need to add new fragment and cannot 760 * do this because interface is non-SG, 761 * or because all the page slots are 762 * busy. */ 763 tcp_mark_push(tp, skb); 764 goto new_segment; 765 } else if (page) { 766 if (off == PAGE_SIZE) { 767 put_page(page); 768 TCP_PAGE(sk) = page = NULL; 769 off = 0; 770 } 771 } else 772 off = 0; 773 774 if (copy > PAGE_SIZE - off) 775 copy = PAGE_SIZE - off; 776 777 if (!sk_stream_wmem_schedule(sk, copy)) 778 goto wait_for_memory; 779 780 if (!page) { 781 /* Allocate new cache page. */ 782 if (!(page = sk_stream_alloc_page(sk))) 783 goto wait_for_memory; 784 } 785 786 /* Time to copy data. We are close to 787 * the end! */ 788 err = skb_copy_to_page(sk, from, skb, page, 789 off, copy); 790 if (err) { 791 /* If this page was new, give it to the 792 * socket so it does not get leaked. 793 */ 794 if (!TCP_PAGE(sk)) { 795 TCP_PAGE(sk) = page; 796 TCP_OFF(sk) = 0; 797 } 798 goto do_error; 799 } 800 801 /* Update the skb. */ 802 if (merge) { 803 skb_shinfo(skb)->frags[i - 1].size += 804 copy; 805 } else { 806 skb_fill_page_desc(skb, i, page, off, copy); 807 if (TCP_PAGE(sk)) { 808 get_page(page); 809 } else if (off + copy < PAGE_SIZE) { 810 get_page(page); 811 TCP_PAGE(sk) = page; 812 } 813 } 814 815 TCP_OFF(sk) = off + copy; 816 } 817 818 if (!copied) 819 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 820 821 tp->write_seq += copy; 822 TCP_SKB_CB(skb)->end_seq += copy; 823 skb_shinfo(skb)->gso_segs = 0; 824 825 from += copy; 826 copied += copy; 827 if ((seglen -= copy) == 0 && iovlen == 0) 828 goto out; 829 830 if (skb->len < mss_now || (flags & MSG_OOB)) 831 continue; 832 833 if (forced_push(tp)) { 834 tcp_mark_push(tp, skb); 835 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 836 } else if (skb == tcp_send_head(sk)) 837 tcp_push_one(sk, mss_now); 838 continue; 839 840 wait_for_sndbuf: 841 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 842 wait_for_memory: 843 if (copied) 844 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 845 846 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 847 goto do_error; 848 849 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 850 size_goal = tp->xmit_size_goal; 851 } 852 } 853 854 out: 855 if (copied) 856 tcp_push(sk, flags, mss_now, tp->nonagle); 857 TCP_CHECK_TIMER(sk); 858 release_sock(sk); 859 return copied; 860 861 do_fault: 862 if (!skb->len) { 863 tcp_unlink_write_queue(skb, sk); 864 /* It is the one place in all of TCP, except connection 865 * reset, where we can be unlinking the send_head. 866 */ 867 tcp_check_send_head(sk, skb); 868 sk_stream_free_skb(sk, skb); 869 } 870 871 do_error: 872 if (copied) 873 goto out; 874 out_err: 875 err = sk_stream_error(sk, flags, err); 876 TCP_CHECK_TIMER(sk); 877 release_sock(sk); 878 return err; 879 } 880 881 /* 882 * Handle reading urgent data. BSD has very simple semantics for 883 * this, no blocking and very strange errors 8) 884 */ 885 886 static int tcp_recv_urg(struct sock *sk, long timeo, 887 struct msghdr *msg, int len, int flags, 888 int *addr_len) 889 { 890 struct tcp_sock *tp = tcp_sk(sk); 891 892 /* No URG data to read. */ 893 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 894 tp->urg_data == TCP_URG_READ) 895 return -EINVAL; /* Yes this is right ! */ 896 897 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 898 return -ENOTCONN; 899 900 if (tp->urg_data & TCP_URG_VALID) { 901 int err = 0; 902 char c = tp->urg_data; 903 904 if (!(flags & MSG_PEEK)) 905 tp->urg_data = TCP_URG_READ; 906 907 /* Read urgent data. */ 908 msg->msg_flags |= MSG_OOB; 909 910 if (len > 0) { 911 if (!(flags & MSG_TRUNC)) 912 err = memcpy_toiovec(msg->msg_iov, &c, 1); 913 len = 1; 914 } else 915 msg->msg_flags |= MSG_TRUNC; 916 917 return err ? -EFAULT : len; 918 } 919 920 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 921 return 0; 922 923 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 924 * the available implementations agree in this case: 925 * this call should never block, independent of the 926 * blocking state of the socket. 927 * Mike <pall@rz.uni-karlsruhe.de> 928 */ 929 return -EAGAIN; 930 } 931 932 /* Clean up the receive buffer for full frames taken by the user, 933 * then send an ACK if necessary. COPIED is the number of bytes 934 * tcp_recvmsg has given to the user so far, it speeds up the 935 * calculation of whether or not we must ACK for the sake of 936 * a window update. 937 */ 938 void tcp_cleanup_rbuf(struct sock *sk, int copied) 939 { 940 struct tcp_sock *tp = tcp_sk(sk); 941 int time_to_ack = 0; 942 943 #if TCP_DEBUG 944 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 945 946 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)); 947 #endif 948 949 if (inet_csk_ack_scheduled(sk)) { 950 const struct inet_connection_sock *icsk = inet_csk(sk); 951 /* Delayed ACKs frequently hit locked sockets during bulk 952 * receive. */ 953 if (icsk->icsk_ack.blocked || 954 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 955 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 956 /* 957 * If this read emptied read buffer, we send ACK, if 958 * connection is not bidirectional, user drained 959 * receive buffer and there was a small segment 960 * in queue. 961 */ 962 (copied > 0 && 963 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 964 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 965 !icsk->icsk_ack.pingpong)) && 966 !atomic_read(&sk->sk_rmem_alloc))) 967 time_to_ack = 1; 968 } 969 970 /* We send an ACK if we can now advertise a non-zero window 971 * which has been raised "significantly". 972 * 973 * Even if window raised up to infinity, do not send window open ACK 974 * in states, where we will not receive more. It is useless. 975 */ 976 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 977 __u32 rcv_window_now = tcp_receive_window(tp); 978 979 /* Optimize, __tcp_select_window() is not cheap. */ 980 if (2*rcv_window_now <= tp->window_clamp) { 981 __u32 new_window = __tcp_select_window(sk); 982 983 /* Send ACK now, if this read freed lots of space 984 * in our buffer. Certainly, new_window is new window. 985 * We can advertise it now, if it is not less than current one. 986 * "Lots" means "at least twice" here. 987 */ 988 if (new_window && new_window >= 2 * rcv_window_now) 989 time_to_ack = 1; 990 } 991 } 992 if (time_to_ack) 993 tcp_send_ack(sk); 994 } 995 996 static void tcp_prequeue_process(struct sock *sk) 997 { 998 struct sk_buff *skb; 999 struct tcp_sock *tp = tcp_sk(sk); 1000 1001 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED); 1002 1003 /* RX process wants to run with disabled BHs, though it is not 1004 * necessary */ 1005 local_bh_disable(); 1006 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1007 sk->sk_backlog_rcv(sk, skb); 1008 local_bh_enable(); 1009 1010 /* Clear memory counter. */ 1011 tp->ucopy.memory = 0; 1012 } 1013 1014 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1015 { 1016 struct sk_buff *skb; 1017 u32 offset; 1018 1019 skb_queue_walk(&sk->sk_receive_queue, skb) { 1020 offset = seq - TCP_SKB_CB(skb)->seq; 1021 if (tcp_hdr(skb)->syn) 1022 offset--; 1023 if (offset < skb->len || tcp_hdr(skb)->fin) { 1024 *off = offset; 1025 return skb; 1026 } 1027 } 1028 return NULL; 1029 } 1030 1031 /* 1032 * This routine provides an alternative to tcp_recvmsg() for routines 1033 * that would like to handle copying from skbuffs directly in 'sendfile' 1034 * fashion. 1035 * Note: 1036 * - It is assumed that the socket was locked by the caller. 1037 * - The routine does not block. 1038 * - At present, there is no support for reading OOB data 1039 * or for 'peeking' the socket using this routine 1040 * (although both would be easy to implement). 1041 */ 1042 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1043 sk_read_actor_t recv_actor) 1044 { 1045 struct sk_buff *skb; 1046 struct tcp_sock *tp = tcp_sk(sk); 1047 u32 seq = tp->copied_seq; 1048 u32 offset; 1049 int copied = 0; 1050 1051 if (sk->sk_state == TCP_LISTEN) 1052 return -ENOTCONN; 1053 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1054 if (offset < skb->len) { 1055 size_t used, len; 1056 1057 len = skb->len - offset; 1058 /* Stop reading if we hit a patch of urgent data */ 1059 if (tp->urg_data) { 1060 u32 urg_offset = tp->urg_seq - seq; 1061 if (urg_offset < len) 1062 len = urg_offset; 1063 if (!len) 1064 break; 1065 } 1066 used = recv_actor(desc, skb, offset, len); 1067 if (used < 0) { 1068 if (!copied) 1069 copied = used; 1070 break; 1071 } else if (used <= len) { 1072 seq += used; 1073 copied += used; 1074 offset += used; 1075 } 1076 if (offset != skb->len) 1077 break; 1078 } 1079 if (tcp_hdr(skb)->fin) { 1080 sk_eat_skb(sk, skb, 0); 1081 ++seq; 1082 break; 1083 } 1084 sk_eat_skb(sk, skb, 0); 1085 if (!desc->count) 1086 break; 1087 } 1088 tp->copied_seq = seq; 1089 1090 tcp_rcv_space_adjust(sk); 1091 1092 /* Clean up data we have read: This will do ACK frames. */ 1093 if (copied > 0) 1094 tcp_cleanup_rbuf(sk, copied); 1095 return copied; 1096 } 1097 1098 /* 1099 * This routine copies from a sock struct into the user buffer. 1100 * 1101 * Technical note: in 2.3 we work on _locked_ socket, so that 1102 * tricks with *seq access order and skb->users are not required. 1103 * Probably, code can be easily improved even more. 1104 */ 1105 1106 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1107 size_t len, int nonblock, int flags, int *addr_len) 1108 { 1109 struct tcp_sock *tp = tcp_sk(sk); 1110 int copied = 0; 1111 u32 peek_seq; 1112 u32 *seq; 1113 unsigned long used; 1114 int err; 1115 int target; /* Read at least this many bytes */ 1116 long timeo; 1117 struct task_struct *user_recv = NULL; 1118 int copied_early = 0; 1119 struct sk_buff *skb; 1120 1121 lock_sock(sk); 1122 1123 TCP_CHECK_TIMER(sk); 1124 1125 err = -ENOTCONN; 1126 if (sk->sk_state == TCP_LISTEN) 1127 goto out; 1128 1129 timeo = sock_rcvtimeo(sk, nonblock); 1130 1131 /* Urgent data needs to be handled specially. */ 1132 if (flags & MSG_OOB) 1133 goto recv_urg; 1134 1135 seq = &tp->copied_seq; 1136 if (flags & MSG_PEEK) { 1137 peek_seq = tp->copied_seq; 1138 seq = &peek_seq; 1139 } 1140 1141 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1142 1143 #ifdef CONFIG_NET_DMA 1144 tp->ucopy.dma_chan = NULL; 1145 preempt_disable(); 1146 skb = skb_peek_tail(&sk->sk_receive_queue); 1147 { 1148 int available = 0; 1149 1150 if (skb) 1151 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); 1152 if ((available < target) && 1153 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1154 !sysctl_tcp_low_latency && 1155 __get_cpu_var(softnet_data).net_dma) { 1156 preempt_enable_no_resched(); 1157 tp->ucopy.pinned_list = 1158 dma_pin_iovec_pages(msg->msg_iov, len); 1159 } else { 1160 preempt_enable_no_resched(); 1161 } 1162 } 1163 #endif 1164 1165 do { 1166 u32 offset; 1167 1168 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1169 if (tp->urg_data && tp->urg_seq == *seq) { 1170 if (copied) 1171 break; 1172 if (signal_pending(current)) { 1173 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1174 break; 1175 } 1176 } 1177 1178 /* Next get a buffer. */ 1179 1180 skb = skb_peek(&sk->sk_receive_queue); 1181 do { 1182 if (!skb) 1183 break; 1184 1185 /* Now that we have two receive queues this 1186 * shouldn't happen. 1187 */ 1188 if (before(*seq, TCP_SKB_CB(skb)->seq)) { 1189 printk(KERN_INFO "recvmsg bug: copied %X " 1190 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq); 1191 break; 1192 } 1193 offset = *seq - TCP_SKB_CB(skb)->seq; 1194 if (tcp_hdr(skb)->syn) 1195 offset--; 1196 if (offset < skb->len) 1197 goto found_ok_skb; 1198 if (tcp_hdr(skb)->fin) 1199 goto found_fin_ok; 1200 BUG_TRAP(flags & MSG_PEEK); 1201 skb = skb->next; 1202 } while (skb != (struct sk_buff *)&sk->sk_receive_queue); 1203 1204 /* Well, if we have backlog, try to process it now yet. */ 1205 1206 if (copied >= target && !sk->sk_backlog.tail) 1207 break; 1208 1209 if (copied) { 1210 if (sk->sk_err || 1211 sk->sk_state == TCP_CLOSE || 1212 (sk->sk_shutdown & RCV_SHUTDOWN) || 1213 !timeo || 1214 signal_pending(current) || 1215 (flags & MSG_PEEK)) 1216 break; 1217 } else { 1218 if (sock_flag(sk, SOCK_DONE)) 1219 break; 1220 1221 if (sk->sk_err) { 1222 copied = sock_error(sk); 1223 break; 1224 } 1225 1226 if (sk->sk_shutdown & RCV_SHUTDOWN) 1227 break; 1228 1229 if (sk->sk_state == TCP_CLOSE) { 1230 if (!sock_flag(sk, SOCK_DONE)) { 1231 /* This occurs when user tries to read 1232 * from never connected socket. 1233 */ 1234 copied = -ENOTCONN; 1235 break; 1236 } 1237 break; 1238 } 1239 1240 if (!timeo) { 1241 copied = -EAGAIN; 1242 break; 1243 } 1244 1245 if (signal_pending(current)) { 1246 copied = sock_intr_errno(timeo); 1247 break; 1248 } 1249 } 1250 1251 tcp_cleanup_rbuf(sk, copied); 1252 1253 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1254 /* Install new reader */ 1255 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1256 user_recv = current; 1257 tp->ucopy.task = user_recv; 1258 tp->ucopy.iov = msg->msg_iov; 1259 } 1260 1261 tp->ucopy.len = len; 1262 1263 BUG_TRAP(tp->copied_seq == tp->rcv_nxt || 1264 (flags & (MSG_PEEK | MSG_TRUNC))); 1265 1266 /* Ugly... If prequeue is not empty, we have to 1267 * process it before releasing socket, otherwise 1268 * order will be broken at second iteration. 1269 * More elegant solution is required!!! 1270 * 1271 * Look: we have the following (pseudo)queues: 1272 * 1273 * 1. packets in flight 1274 * 2. backlog 1275 * 3. prequeue 1276 * 4. receive_queue 1277 * 1278 * Each queue can be processed only if the next ones 1279 * are empty. At this point we have empty receive_queue. 1280 * But prequeue _can_ be not empty after 2nd iteration, 1281 * when we jumped to start of loop because backlog 1282 * processing added something to receive_queue. 1283 * We cannot release_sock(), because backlog contains 1284 * packets arrived _after_ prequeued ones. 1285 * 1286 * Shortly, algorithm is clear --- to process all 1287 * the queues in order. We could make it more directly, 1288 * requeueing packets from backlog to prequeue, if 1289 * is not empty. It is more elegant, but eats cycles, 1290 * unfortunately. 1291 */ 1292 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1293 goto do_prequeue; 1294 1295 /* __ Set realtime policy in scheduler __ */ 1296 } 1297 1298 if (copied >= target) { 1299 /* Do not sleep, just process backlog. */ 1300 release_sock(sk); 1301 lock_sock(sk); 1302 } else 1303 sk_wait_data(sk, &timeo); 1304 1305 #ifdef CONFIG_NET_DMA 1306 tp->ucopy.wakeup = 0; 1307 #endif 1308 1309 if (user_recv) { 1310 int chunk; 1311 1312 /* __ Restore normal policy in scheduler __ */ 1313 1314 if ((chunk = len - tp->ucopy.len) != 0) { 1315 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1316 len -= chunk; 1317 copied += chunk; 1318 } 1319 1320 if (tp->rcv_nxt == tp->copied_seq && 1321 !skb_queue_empty(&tp->ucopy.prequeue)) { 1322 do_prequeue: 1323 tcp_prequeue_process(sk); 1324 1325 if ((chunk = len - tp->ucopy.len) != 0) { 1326 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1327 len -= chunk; 1328 copied += chunk; 1329 } 1330 } 1331 } 1332 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) { 1333 if (net_ratelimit()) 1334 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n", 1335 current->comm, current->pid); 1336 peek_seq = tp->copied_seq; 1337 } 1338 continue; 1339 1340 found_ok_skb: 1341 /* Ok so how much can we use? */ 1342 used = skb->len - offset; 1343 if (len < used) 1344 used = len; 1345 1346 /* Do we have urgent data here? */ 1347 if (tp->urg_data) { 1348 u32 urg_offset = tp->urg_seq - *seq; 1349 if (urg_offset < used) { 1350 if (!urg_offset) { 1351 if (!sock_flag(sk, SOCK_URGINLINE)) { 1352 ++*seq; 1353 offset++; 1354 used--; 1355 if (!used) 1356 goto skip_copy; 1357 } 1358 } else 1359 used = urg_offset; 1360 } 1361 } 1362 1363 if (!(flags & MSG_TRUNC)) { 1364 #ifdef CONFIG_NET_DMA 1365 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1366 tp->ucopy.dma_chan = get_softnet_dma(); 1367 1368 if (tp->ucopy.dma_chan) { 1369 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1370 tp->ucopy.dma_chan, skb, offset, 1371 msg->msg_iov, used, 1372 tp->ucopy.pinned_list); 1373 1374 if (tp->ucopy.dma_cookie < 0) { 1375 1376 printk(KERN_ALERT "dma_cookie < 0\n"); 1377 1378 /* Exception. Bailout! */ 1379 if (!copied) 1380 copied = -EFAULT; 1381 break; 1382 } 1383 if ((offset + used) == skb->len) 1384 copied_early = 1; 1385 1386 } else 1387 #endif 1388 { 1389 err = skb_copy_datagram_iovec(skb, offset, 1390 msg->msg_iov, used); 1391 if (err) { 1392 /* Exception. Bailout! */ 1393 if (!copied) 1394 copied = -EFAULT; 1395 break; 1396 } 1397 } 1398 } 1399 1400 *seq += used; 1401 copied += used; 1402 len -= used; 1403 1404 tcp_rcv_space_adjust(sk); 1405 1406 skip_copy: 1407 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1408 tp->urg_data = 0; 1409 tcp_fast_path_check(sk); 1410 } 1411 if (used + offset < skb->len) 1412 continue; 1413 1414 if (tcp_hdr(skb)->fin) 1415 goto found_fin_ok; 1416 if (!(flags & MSG_PEEK)) { 1417 sk_eat_skb(sk, skb, copied_early); 1418 copied_early = 0; 1419 } 1420 continue; 1421 1422 found_fin_ok: 1423 /* Process the FIN. */ 1424 ++*seq; 1425 if (!(flags & MSG_PEEK)) { 1426 sk_eat_skb(sk, skb, copied_early); 1427 copied_early = 0; 1428 } 1429 break; 1430 } while (len > 0); 1431 1432 if (user_recv) { 1433 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1434 int chunk; 1435 1436 tp->ucopy.len = copied > 0 ? len : 0; 1437 1438 tcp_prequeue_process(sk); 1439 1440 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1441 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1442 len -= chunk; 1443 copied += chunk; 1444 } 1445 } 1446 1447 tp->ucopy.task = NULL; 1448 tp->ucopy.len = 0; 1449 } 1450 1451 #ifdef CONFIG_NET_DMA 1452 if (tp->ucopy.dma_chan) { 1453 dma_cookie_t done, used; 1454 1455 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1456 1457 while (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1458 tp->ucopy.dma_cookie, &done, 1459 &used) == DMA_IN_PROGRESS) { 1460 /* do partial cleanup of sk_async_wait_queue */ 1461 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1462 (dma_async_is_complete(skb->dma_cookie, done, 1463 used) == DMA_SUCCESS)) { 1464 __skb_dequeue(&sk->sk_async_wait_queue); 1465 kfree_skb(skb); 1466 } 1467 } 1468 1469 /* Safe to free early-copied skbs now */ 1470 __skb_queue_purge(&sk->sk_async_wait_queue); 1471 dma_chan_put(tp->ucopy.dma_chan); 1472 tp->ucopy.dma_chan = NULL; 1473 } 1474 if (tp->ucopy.pinned_list) { 1475 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1476 tp->ucopy.pinned_list = NULL; 1477 } 1478 #endif 1479 1480 /* According to UNIX98, msg_name/msg_namelen are ignored 1481 * on connected socket. I was just happy when found this 8) --ANK 1482 */ 1483 1484 /* Clean up data we have read: This will do ACK frames. */ 1485 tcp_cleanup_rbuf(sk, copied); 1486 1487 TCP_CHECK_TIMER(sk); 1488 release_sock(sk); 1489 return copied; 1490 1491 out: 1492 TCP_CHECK_TIMER(sk); 1493 release_sock(sk); 1494 return err; 1495 1496 recv_urg: 1497 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); 1498 goto out; 1499 } 1500 1501 /* 1502 * State processing on a close. This implements the state shift for 1503 * sending our FIN frame. Note that we only send a FIN for some 1504 * states. A shutdown() may have already sent the FIN, or we may be 1505 * closed. 1506 */ 1507 1508 static const unsigned char new_state[16] = { 1509 /* current state: new state: action: */ 1510 /* (Invalid) */ TCP_CLOSE, 1511 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1512 /* TCP_SYN_SENT */ TCP_CLOSE, 1513 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1514 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1515 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1516 /* TCP_TIME_WAIT */ TCP_CLOSE, 1517 /* TCP_CLOSE */ TCP_CLOSE, 1518 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1519 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1520 /* TCP_LISTEN */ TCP_CLOSE, 1521 /* TCP_CLOSING */ TCP_CLOSING, 1522 }; 1523 1524 static int tcp_close_state(struct sock *sk) 1525 { 1526 int next = (int)new_state[sk->sk_state]; 1527 int ns = next & TCP_STATE_MASK; 1528 1529 tcp_set_state(sk, ns); 1530 1531 return next & TCP_ACTION_FIN; 1532 } 1533 1534 /* 1535 * Shutdown the sending side of a connection. Much like close except 1536 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD). 1537 */ 1538 1539 void tcp_shutdown(struct sock *sk, int how) 1540 { 1541 /* We need to grab some memory, and put together a FIN, 1542 * and then put it into the queue to be sent. 1543 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1544 */ 1545 if (!(how & SEND_SHUTDOWN)) 1546 return; 1547 1548 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1549 if ((1 << sk->sk_state) & 1550 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1551 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1552 /* Clear out any half completed packets. FIN if needed. */ 1553 if (tcp_close_state(sk)) 1554 tcp_send_fin(sk); 1555 } 1556 } 1557 1558 void tcp_close(struct sock *sk, long timeout) 1559 { 1560 struct sk_buff *skb; 1561 int data_was_unread = 0; 1562 int state; 1563 1564 lock_sock(sk); 1565 sk->sk_shutdown = SHUTDOWN_MASK; 1566 1567 if (sk->sk_state == TCP_LISTEN) { 1568 tcp_set_state(sk, TCP_CLOSE); 1569 1570 /* Special case. */ 1571 inet_csk_listen_stop(sk); 1572 1573 goto adjudge_to_death; 1574 } 1575 1576 /* We need to flush the recv. buffs. We do this only on the 1577 * descriptor close, not protocol-sourced closes, because the 1578 * reader process may not have drained the data yet! 1579 */ 1580 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 1581 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 1582 tcp_hdr(skb)->fin; 1583 data_was_unread += len; 1584 __kfree_skb(skb); 1585 } 1586 1587 sk_stream_mem_reclaim(sk); 1588 1589 /* As outlined in RFC 2525, section 2.17, we send a RST here because 1590 * data was lost. To witness the awful effects of the old behavior of 1591 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 1592 * GET in an FTP client, suspend the process, wait for the client to 1593 * advertise a zero window, then kill -9 the FTP client, wheee... 1594 * Note: timeout is always zero in such a case. 1595 */ 1596 if (data_was_unread) { 1597 /* Unread data was tossed, zap the connection. */ 1598 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE); 1599 tcp_set_state(sk, TCP_CLOSE); 1600 tcp_send_active_reset(sk, GFP_KERNEL); 1601 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 1602 /* Check zero linger _after_ checking for unread data. */ 1603 sk->sk_prot->disconnect(sk, 0); 1604 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA); 1605 } else if (tcp_close_state(sk)) { 1606 /* We FIN if the application ate all the data before 1607 * zapping the connection. 1608 */ 1609 1610 /* RED-PEN. Formally speaking, we have broken TCP state 1611 * machine. State transitions: 1612 * 1613 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 1614 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 1615 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 1616 * 1617 * are legal only when FIN has been sent (i.e. in window), 1618 * rather than queued out of window. Purists blame. 1619 * 1620 * F.e. "RFC state" is ESTABLISHED, 1621 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 1622 * 1623 * The visible declinations are that sometimes 1624 * we enter time-wait state, when it is not required really 1625 * (harmless), do not send active resets, when they are 1626 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 1627 * they look as CLOSING or LAST_ACK for Linux) 1628 * Probably, I missed some more holelets. 1629 * --ANK 1630 */ 1631 tcp_send_fin(sk); 1632 } 1633 1634 sk_stream_wait_close(sk, timeout); 1635 1636 adjudge_to_death: 1637 state = sk->sk_state; 1638 sock_hold(sk); 1639 sock_orphan(sk); 1640 atomic_inc(sk->sk_prot->orphan_count); 1641 1642 /* It is the last release_sock in its life. It will remove backlog. */ 1643 release_sock(sk); 1644 1645 1646 /* Now socket is owned by kernel and we acquire BH lock 1647 to finish close. No need to check for user refs. 1648 */ 1649 local_bh_disable(); 1650 bh_lock_sock(sk); 1651 BUG_TRAP(!sock_owned_by_user(sk)); 1652 1653 /* Have we already been destroyed by a softirq or backlog? */ 1654 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 1655 goto out; 1656 1657 /* This is a (useful) BSD violating of the RFC. There is a 1658 * problem with TCP as specified in that the other end could 1659 * keep a socket open forever with no application left this end. 1660 * We use a 3 minute timeout (about the same as BSD) then kill 1661 * our end. If they send after that then tough - BUT: long enough 1662 * that we won't make the old 4*rto = almost no time - whoops 1663 * reset mistake. 1664 * 1665 * Nope, it was not mistake. It is really desired behaviour 1666 * f.e. on http servers, when such sockets are useless, but 1667 * consume significant resources. Let's do it with special 1668 * linger2 option. --ANK 1669 */ 1670 1671 if (sk->sk_state == TCP_FIN_WAIT2) { 1672 struct tcp_sock *tp = tcp_sk(sk); 1673 if (tp->linger2 < 0) { 1674 tcp_set_state(sk, TCP_CLOSE); 1675 tcp_send_active_reset(sk, GFP_ATOMIC); 1676 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER); 1677 } else { 1678 const int tmo = tcp_fin_time(sk); 1679 1680 if (tmo > TCP_TIMEWAIT_LEN) { 1681 inet_csk_reset_keepalive_timer(sk, 1682 tmo - TCP_TIMEWAIT_LEN); 1683 } else { 1684 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 1685 goto out; 1686 } 1687 } 1688 } 1689 if (sk->sk_state != TCP_CLOSE) { 1690 sk_stream_mem_reclaim(sk); 1691 if (tcp_too_many_orphans(sk, 1692 atomic_read(sk->sk_prot->orphan_count))) { 1693 if (net_ratelimit()) 1694 printk(KERN_INFO "TCP: too many of orphaned " 1695 "sockets\n"); 1696 tcp_set_state(sk, TCP_CLOSE); 1697 tcp_send_active_reset(sk, GFP_ATOMIC); 1698 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY); 1699 } 1700 } 1701 1702 if (sk->sk_state == TCP_CLOSE) 1703 inet_csk_destroy_sock(sk); 1704 /* Otherwise, socket is reprieved until protocol close. */ 1705 1706 out: 1707 bh_unlock_sock(sk); 1708 local_bh_enable(); 1709 sock_put(sk); 1710 } 1711 1712 /* These states need RST on ABORT according to RFC793 */ 1713 1714 static inline int tcp_need_reset(int state) 1715 { 1716 return (1 << state) & 1717 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 1718 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 1719 } 1720 1721 int tcp_disconnect(struct sock *sk, int flags) 1722 { 1723 struct inet_sock *inet = inet_sk(sk); 1724 struct inet_connection_sock *icsk = inet_csk(sk); 1725 struct tcp_sock *tp = tcp_sk(sk); 1726 int err = 0; 1727 int old_state = sk->sk_state; 1728 1729 if (old_state != TCP_CLOSE) 1730 tcp_set_state(sk, TCP_CLOSE); 1731 1732 /* ABORT function of RFC793 */ 1733 if (old_state == TCP_LISTEN) { 1734 inet_csk_listen_stop(sk); 1735 } else if (tcp_need_reset(old_state) || 1736 (tp->snd_nxt != tp->write_seq && 1737 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 1738 /* The last check adjusts for discrepancy of Linux wrt. RFC 1739 * states 1740 */ 1741 tcp_send_active_reset(sk, gfp_any()); 1742 sk->sk_err = ECONNRESET; 1743 } else if (old_state == TCP_SYN_SENT) 1744 sk->sk_err = ECONNRESET; 1745 1746 tcp_clear_xmit_timers(sk); 1747 __skb_queue_purge(&sk->sk_receive_queue); 1748 tcp_write_queue_purge(sk); 1749 __skb_queue_purge(&tp->out_of_order_queue); 1750 #ifdef CONFIG_NET_DMA 1751 __skb_queue_purge(&sk->sk_async_wait_queue); 1752 #endif 1753 1754 inet->dport = 0; 1755 1756 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 1757 inet_reset_saddr(sk); 1758 1759 sk->sk_shutdown = 0; 1760 sock_reset_flag(sk, SOCK_DONE); 1761 tp->srtt = 0; 1762 if ((tp->write_seq += tp->max_window + 2) == 0) 1763 tp->write_seq = 1; 1764 icsk->icsk_backoff = 0; 1765 tp->snd_cwnd = 2; 1766 icsk->icsk_probes_out = 0; 1767 tp->packets_out = 0; 1768 tp->snd_ssthresh = 0x7fffffff; 1769 tp->snd_cwnd_cnt = 0; 1770 tp->bytes_acked = 0; 1771 tcp_set_ca_state(sk, TCP_CA_Open); 1772 tcp_clear_retrans(tp); 1773 inet_csk_delack_init(sk); 1774 tcp_init_send_head(sk); 1775 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 1776 __sk_dst_reset(sk); 1777 1778 BUG_TRAP(!inet->num || icsk->icsk_bind_hash); 1779 1780 sk->sk_error_report(sk); 1781 return err; 1782 } 1783 1784 /* 1785 * Socket option code for TCP. 1786 */ 1787 static int do_tcp_setsockopt(struct sock *sk, int level, 1788 int optname, char __user *optval, int optlen) 1789 { 1790 struct tcp_sock *tp = tcp_sk(sk); 1791 struct inet_connection_sock *icsk = inet_csk(sk); 1792 int val; 1793 int err = 0; 1794 1795 /* This is a string value all the others are int's */ 1796 if (optname == TCP_CONGESTION) { 1797 char name[TCP_CA_NAME_MAX]; 1798 1799 if (optlen < 1) 1800 return -EINVAL; 1801 1802 val = strncpy_from_user(name, optval, 1803 min(TCP_CA_NAME_MAX-1, optlen)); 1804 if (val < 0) 1805 return -EFAULT; 1806 name[val] = 0; 1807 1808 lock_sock(sk); 1809 err = tcp_set_congestion_control(sk, name); 1810 release_sock(sk); 1811 return err; 1812 } 1813 1814 if (optlen < sizeof(int)) 1815 return -EINVAL; 1816 1817 if (get_user(val, (int __user *)optval)) 1818 return -EFAULT; 1819 1820 lock_sock(sk); 1821 1822 switch (optname) { 1823 case TCP_MAXSEG: 1824 /* Values greater than interface MTU won't take effect. However 1825 * at the point when this call is done we typically don't yet 1826 * know which interface is going to be used */ 1827 if (val < 8 || val > MAX_TCP_WINDOW) { 1828 err = -EINVAL; 1829 break; 1830 } 1831 tp->rx_opt.user_mss = val; 1832 break; 1833 1834 case TCP_NODELAY: 1835 if (val) { 1836 /* TCP_NODELAY is weaker than TCP_CORK, so that 1837 * this option on corked socket is remembered, but 1838 * it is not activated until cork is cleared. 1839 * 1840 * However, when TCP_NODELAY is set we make 1841 * an explicit push, which overrides even TCP_CORK 1842 * for currently queued segments. 1843 */ 1844 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 1845 tcp_push_pending_frames(sk); 1846 } else { 1847 tp->nonagle &= ~TCP_NAGLE_OFF; 1848 } 1849 break; 1850 1851 case TCP_CORK: 1852 /* When set indicates to always queue non-full frames. 1853 * Later the user clears this option and we transmit 1854 * any pending partial frames in the queue. This is 1855 * meant to be used alongside sendfile() to get properly 1856 * filled frames when the user (for example) must write 1857 * out headers with a write() call first and then use 1858 * sendfile to send out the data parts. 1859 * 1860 * TCP_CORK can be set together with TCP_NODELAY and it is 1861 * stronger than TCP_NODELAY. 1862 */ 1863 if (val) { 1864 tp->nonagle |= TCP_NAGLE_CORK; 1865 } else { 1866 tp->nonagle &= ~TCP_NAGLE_CORK; 1867 if (tp->nonagle&TCP_NAGLE_OFF) 1868 tp->nonagle |= TCP_NAGLE_PUSH; 1869 tcp_push_pending_frames(sk); 1870 } 1871 break; 1872 1873 case TCP_KEEPIDLE: 1874 if (val < 1 || val > MAX_TCP_KEEPIDLE) 1875 err = -EINVAL; 1876 else { 1877 tp->keepalive_time = val * HZ; 1878 if (sock_flag(sk, SOCK_KEEPOPEN) && 1879 !((1 << sk->sk_state) & 1880 (TCPF_CLOSE | TCPF_LISTEN))) { 1881 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp; 1882 if (tp->keepalive_time > elapsed) 1883 elapsed = tp->keepalive_time - elapsed; 1884 else 1885 elapsed = 0; 1886 inet_csk_reset_keepalive_timer(sk, elapsed); 1887 } 1888 } 1889 break; 1890 case TCP_KEEPINTVL: 1891 if (val < 1 || val > MAX_TCP_KEEPINTVL) 1892 err = -EINVAL; 1893 else 1894 tp->keepalive_intvl = val * HZ; 1895 break; 1896 case TCP_KEEPCNT: 1897 if (val < 1 || val > MAX_TCP_KEEPCNT) 1898 err = -EINVAL; 1899 else 1900 tp->keepalive_probes = val; 1901 break; 1902 case TCP_SYNCNT: 1903 if (val < 1 || val > MAX_TCP_SYNCNT) 1904 err = -EINVAL; 1905 else 1906 icsk->icsk_syn_retries = val; 1907 break; 1908 1909 case TCP_LINGER2: 1910 if (val < 0) 1911 tp->linger2 = -1; 1912 else if (val > sysctl_tcp_fin_timeout / HZ) 1913 tp->linger2 = 0; 1914 else 1915 tp->linger2 = val * HZ; 1916 break; 1917 1918 case TCP_DEFER_ACCEPT: 1919 icsk->icsk_accept_queue.rskq_defer_accept = 0; 1920 if (val > 0) { 1921 /* Translate value in seconds to number of 1922 * retransmits */ 1923 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 && 1924 val > ((TCP_TIMEOUT_INIT / HZ) << 1925 icsk->icsk_accept_queue.rskq_defer_accept)) 1926 icsk->icsk_accept_queue.rskq_defer_accept++; 1927 icsk->icsk_accept_queue.rskq_defer_accept++; 1928 } 1929 break; 1930 1931 case TCP_WINDOW_CLAMP: 1932 if (!val) { 1933 if (sk->sk_state != TCP_CLOSE) { 1934 err = -EINVAL; 1935 break; 1936 } 1937 tp->window_clamp = 0; 1938 } else 1939 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 1940 SOCK_MIN_RCVBUF / 2 : val; 1941 break; 1942 1943 case TCP_QUICKACK: 1944 if (!val) { 1945 icsk->icsk_ack.pingpong = 1; 1946 } else { 1947 icsk->icsk_ack.pingpong = 0; 1948 if ((1 << sk->sk_state) & 1949 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 1950 inet_csk_ack_scheduled(sk)) { 1951 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 1952 tcp_cleanup_rbuf(sk, 1); 1953 if (!(val & 1)) 1954 icsk->icsk_ack.pingpong = 1; 1955 } 1956 } 1957 break; 1958 1959 #ifdef CONFIG_TCP_MD5SIG 1960 case TCP_MD5SIG: 1961 /* Read the IP->Key mappings from userspace */ 1962 err = tp->af_specific->md5_parse(sk, optval, optlen); 1963 break; 1964 #endif 1965 1966 default: 1967 err = -ENOPROTOOPT; 1968 break; 1969 } 1970 1971 release_sock(sk); 1972 return err; 1973 } 1974 1975 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 1976 int optlen) 1977 { 1978 struct inet_connection_sock *icsk = inet_csk(sk); 1979 1980 if (level != SOL_TCP) 1981 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 1982 optval, optlen); 1983 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 1984 } 1985 1986 #ifdef CONFIG_COMPAT 1987 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 1988 char __user *optval, int optlen) 1989 { 1990 if (level != SOL_TCP) 1991 return inet_csk_compat_setsockopt(sk, level, optname, 1992 optval, optlen); 1993 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 1994 } 1995 1996 EXPORT_SYMBOL(compat_tcp_setsockopt); 1997 #endif 1998 1999 /* Return information about state of tcp endpoint in API format. */ 2000 void tcp_get_info(struct sock *sk, struct tcp_info *info) 2001 { 2002 struct tcp_sock *tp = tcp_sk(sk); 2003 const struct inet_connection_sock *icsk = inet_csk(sk); 2004 u32 now = tcp_time_stamp; 2005 2006 memset(info, 0, sizeof(*info)); 2007 2008 info->tcpi_state = sk->sk_state; 2009 info->tcpi_ca_state = icsk->icsk_ca_state; 2010 info->tcpi_retransmits = icsk->icsk_retransmits; 2011 info->tcpi_probes = icsk->icsk_probes_out; 2012 info->tcpi_backoff = icsk->icsk_backoff; 2013 2014 if (tp->rx_opt.tstamp_ok) 2015 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2016 if (tp->rx_opt.sack_ok) 2017 info->tcpi_options |= TCPI_OPT_SACK; 2018 if (tp->rx_opt.wscale_ok) { 2019 info->tcpi_options |= TCPI_OPT_WSCALE; 2020 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2021 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2022 } 2023 2024 if (tp->ecn_flags&TCP_ECN_OK) 2025 info->tcpi_options |= TCPI_OPT_ECN; 2026 2027 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2028 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2029 info->tcpi_snd_mss = tp->mss_cache; 2030 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2031 2032 info->tcpi_unacked = tp->packets_out; 2033 info->tcpi_sacked = tp->sacked_out; 2034 info->tcpi_lost = tp->lost_out; 2035 info->tcpi_retrans = tp->retrans_out; 2036 info->tcpi_fackets = tp->fackets_out; 2037 2038 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2039 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2040 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2041 2042 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2043 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2044 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2045 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2046 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2047 info->tcpi_snd_cwnd = tp->snd_cwnd; 2048 info->tcpi_advmss = tp->advmss; 2049 info->tcpi_reordering = tp->reordering; 2050 2051 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2052 info->tcpi_rcv_space = tp->rcvq_space.space; 2053 2054 info->tcpi_total_retrans = tp->total_retrans; 2055 } 2056 2057 EXPORT_SYMBOL_GPL(tcp_get_info); 2058 2059 static int do_tcp_getsockopt(struct sock *sk, int level, 2060 int optname, char __user *optval, int __user *optlen) 2061 { 2062 struct inet_connection_sock *icsk = inet_csk(sk); 2063 struct tcp_sock *tp = tcp_sk(sk); 2064 int val, len; 2065 2066 if (get_user(len, optlen)) 2067 return -EFAULT; 2068 2069 len = min_t(unsigned int, len, sizeof(int)); 2070 2071 if (len < 0) 2072 return -EINVAL; 2073 2074 switch (optname) { 2075 case TCP_MAXSEG: 2076 val = tp->mss_cache; 2077 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2078 val = tp->rx_opt.user_mss; 2079 break; 2080 case TCP_NODELAY: 2081 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2082 break; 2083 case TCP_CORK: 2084 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2085 break; 2086 case TCP_KEEPIDLE: 2087 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ; 2088 break; 2089 case TCP_KEEPINTVL: 2090 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ; 2091 break; 2092 case TCP_KEEPCNT: 2093 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 2094 break; 2095 case TCP_SYNCNT: 2096 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2097 break; 2098 case TCP_LINGER2: 2099 val = tp->linger2; 2100 if (val >= 0) 2101 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2102 break; 2103 case TCP_DEFER_ACCEPT: 2104 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 : 2105 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1)); 2106 break; 2107 case TCP_WINDOW_CLAMP: 2108 val = tp->window_clamp; 2109 break; 2110 case TCP_INFO: { 2111 struct tcp_info info; 2112 2113 if (get_user(len, optlen)) 2114 return -EFAULT; 2115 2116 tcp_get_info(sk, &info); 2117 2118 len = min_t(unsigned int, len, sizeof(info)); 2119 if (put_user(len, optlen)) 2120 return -EFAULT; 2121 if (copy_to_user(optval, &info, len)) 2122 return -EFAULT; 2123 return 0; 2124 } 2125 case TCP_QUICKACK: 2126 val = !icsk->icsk_ack.pingpong; 2127 break; 2128 2129 case TCP_CONGESTION: 2130 if (get_user(len, optlen)) 2131 return -EFAULT; 2132 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2133 if (put_user(len, optlen)) 2134 return -EFAULT; 2135 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2136 return -EFAULT; 2137 return 0; 2138 default: 2139 return -ENOPROTOOPT; 2140 } 2141 2142 if (put_user(len, optlen)) 2143 return -EFAULT; 2144 if (copy_to_user(optval, &val, len)) 2145 return -EFAULT; 2146 return 0; 2147 } 2148 2149 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2150 int __user *optlen) 2151 { 2152 struct inet_connection_sock *icsk = inet_csk(sk); 2153 2154 if (level != SOL_TCP) 2155 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2156 optval, optlen); 2157 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2158 } 2159 2160 #ifdef CONFIG_COMPAT 2161 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2162 char __user *optval, int __user *optlen) 2163 { 2164 if (level != SOL_TCP) 2165 return inet_csk_compat_getsockopt(sk, level, optname, 2166 optval, optlen); 2167 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2168 } 2169 2170 EXPORT_SYMBOL(compat_tcp_getsockopt); 2171 #endif 2172 2173 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features) 2174 { 2175 struct sk_buff *segs = ERR_PTR(-EINVAL); 2176 struct tcphdr *th; 2177 unsigned thlen; 2178 unsigned int seq; 2179 __be32 delta; 2180 unsigned int oldlen; 2181 unsigned int len; 2182 2183 if (!pskb_may_pull(skb, sizeof(*th))) 2184 goto out; 2185 2186 th = tcp_hdr(skb); 2187 thlen = th->doff * 4; 2188 if (thlen < sizeof(*th)) 2189 goto out; 2190 2191 if (!pskb_may_pull(skb, thlen)) 2192 goto out; 2193 2194 oldlen = (u16)~skb->len; 2195 __skb_pull(skb, thlen); 2196 2197 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2198 /* Packet is from an untrusted source, reset gso_segs. */ 2199 int type = skb_shinfo(skb)->gso_type; 2200 int mss; 2201 2202 if (unlikely(type & 2203 ~(SKB_GSO_TCPV4 | 2204 SKB_GSO_DODGY | 2205 SKB_GSO_TCP_ECN | 2206 SKB_GSO_TCPV6 | 2207 0) || 2208 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2209 goto out; 2210 2211 mss = skb_shinfo(skb)->gso_size; 2212 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss; 2213 2214 segs = NULL; 2215 goto out; 2216 } 2217 2218 segs = skb_segment(skb, features); 2219 if (IS_ERR(segs)) 2220 goto out; 2221 2222 len = skb_shinfo(skb)->gso_size; 2223 delta = htonl(oldlen + (thlen + len)); 2224 2225 skb = segs; 2226 th = tcp_hdr(skb); 2227 seq = ntohl(th->seq); 2228 2229 do { 2230 th->fin = th->psh = 0; 2231 2232 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2233 (__force u32)delta)); 2234 if (skb->ip_summed != CHECKSUM_PARTIAL) 2235 th->check = 2236 csum_fold(csum_partial(skb_transport_header(skb), 2237 thlen, skb->csum)); 2238 2239 seq += len; 2240 skb = skb->next; 2241 th = tcp_hdr(skb); 2242 2243 th->seq = htonl(seq); 2244 th->cwr = 0; 2245 } while (skb->next); 2246 2247 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 2248 skb->data_len); 2249 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2250 (__force u32)delta)); 2251 if (skb->ip_summed != CHECKSUM_PARTIAL) 2252 th->check = csum_fold(csum_partial(skb_transport_header(skb), 2253 thlen, skb->csum)); 2254 2255 out: 2256 return segs; 2257 } 2258 EXPORT_SYMBOL(tcp_tso_segment); 2259 2260 #ifdef CONFIG_TCP_MD5SIG 2261 static unsigned long tcp_md5sig_users; 2262 static struct tcp_md5sig_pool **tcp_md5sig_pool; 2263 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 2264 2265 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool) 2266 { 2267 int cpu; 2268 for_each_possible_cpu(cpu) { 2269 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); 2270 if (p) { 2271 if (p->md5_desc.tfm) 2272 crypto_free_hash(p->md5_desc.tfm); 2273 kfree(p); 2274 p = NULL; 2275 } 2276 } 2277 free_percpu(pool); 2278 } 2279 2280 void tcp_free_md5sig_pool(void) 2281 { 2282 struct tcp_md5sig_pool **pool = NULL; 2283 2284 spin_lock_bh(&tcp_md5sig_pool_lock); 2285 if (--tcp_md5sig_users == 0) { 2286 pool = tcp_md5sig_pool; 2287 tcp_md5sig_pool = NULL; 2288 } 2289 spin_unlock_bh(&tcp_md5sig_pool_lock); 2290 if (pool) 2291 __tcp_free_md5sig_pool(pool); 2292 } 2293 2294 EXPORT_SYMBOL(tcp_free_md5sig_pool); 2295 2296 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void) 2297 { 2298 int cpu; 2299 struct tcp_md5sig_pool **pool; 2300 2301 pool = alloc_percpu(struct tcp_md5sig_pool *); 2302 if (!pool) 2303 return NULL; 2304 2305 for_each_possible_cpu(cpu) { 2306 struct tcp_md5sig_pool *p; 2307 struct crypto_hash *hash; 2308 2309 p = kzalloc(sizeof(*p), GFP_KERNEL); 2310 if (!p) 2311 goto out_free; 2312 *per_cpu_ptr(pool, cpu) = p; 2313 2314 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2315 if (!hash || IS_ERR(hash)) 2316 goto out_free; 2317 2318 p->md5_desc.tfm = hash; 2319 } 2320 return pool; 2321 out_free: 2322 __tcp_free_md5sig_pool(pool); 2323 return NULL; 2324 } 2325 2326 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void) 2327 { 2328 struct tcp_md5sig_pool **pool; 2329 int alloc = 0; 2330 2331 retry: 2332 spin_lock_bh(&tcp_md5sig_pool_lock); 2333 pool = tcp_md5sig_pool; 2334 if (tcp_md5sig_users++ == 0) { 2335 alloc = 1; 2336 spin_unlock_bh(&tcp_md5sig_pool_lock); 2337 } else if (!pool) { 2338 tcp_md5sig_users--; 2339 spin_unlock_bh(&tcp_md5sig_pool_lock); 2340 cpu_relax(); 2341 goto retry; 2342 } else 2343 spin_unlock_bh(&tcp_md5sig_pool_lock); 2344 2345 if (alloc) { 2346 /* we cannot hold spinlock here because this may sleep. */ 2347 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(); 2348 spin_lock_bh(&tcp_md5sig_pool_lock); 2349 if (!p) { 2350 tcp_md5sig_users--; 2351 spin_unlock_bh(&tcp_md5sig_pool_lock); 2352 return NULL; 2353 } 2354 pool = tcp_md5sig_pool; 2355 if (pool) { 2356 /* oops, it has already been assigned. */ 2357 spin_unlock_bh(&tcp_md5sig_pool_lock); 2358 __tcp_free_md5sig_pool(p); 2359 } else { 2360 tcp_md5sig_pool = pool = p; 2361 spin_unlock_bh(&tcp_md5sig_pool_lock); 2362 } 2363 } 2364 return pool; 2365 } 2366 2367 EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2368 2369 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu) 2370 { 2371 struct tcp_md5sig_pool **p; 2372 spin_lock_bh(&tcp_md5sig_pool_lock); 2373 p = tcp_md5sig_pool; 2374 if (p) 2375 tcp_md5sig_users++; 2376 spin_unlock_bh(&tcp_md5sig_pool_lock); 2377 return (p ? *per_cpu_ptr(p, cpu) : NULL); 2378 } 2379 2380 EXPORT_SYMBOL(__tcp_get_md5sig_pool); 2381 2382 void __tcp_put_md5sig_pool(void) 2383 { 2384 tcp_free_md5sig_pool(); 2385 } 2386 2387 EXPORT_SYMBOL(__tcp_put_md5sig_pool); 2388 #endif 2389 2390 void tcp_done(struct sock *sk) 2391 { 2392 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 2393 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); 2394 2395 tcp_set_state(sk, TCP_CLOSE); 2396 tcp_clear_xmit_timers(sk); 2397 2398 sk->sk_shutdown = SHUTDOWN_MASK; 2399 2400 if (!sock_flag(sk, SOCK_DEAD)) 2401 sk->sk_state_change(sk); 2402 else 2403 inet_csk_destroy_sock(sk); 2404 } 2405 EXPORT_SYMBOL_GPL(tcp_done); 2406 2407 extern void __skb_cb_too_small_for_tcp(int, int); 2408 extern struct tcp_congestion_ops tcp_reno; 2409 2410 static __initdata unsigned long thash_entries; 2411 static int __init set_thash_entries(char *str) 2412 { 2413 if (!str) 2414 return 0; 2415 thash_entries = simple_strtoul(str, &str, 0); 2416 return 1; 2417 } 2418 __setup("thash_entries=", set_thash_entries); 2419 2420 void __init tcp_init(void) 2421 { 2422 struct sk_buff *skb = NULL; 2423 unsigned long limit; 2424 int order, i, max_share; 2425 2426 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb)) 2427 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb), 2428 sizeof(skb->cb)); 2429 2430 tcp_hashinfo.bind_bucket_cachep = 2431 kmem_cache_create("tcp_bind_bucket", 2432 sizeof(struct inet_bind_bucket), 0, 2433 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2434 2435 /* Size and allocate the main established and bind bucket 2436 * hash tables. 2437 * 2438 * The methodology is similar to that of the buffer cache. 2439 */ 2440 tcp_hashinfo.ehash = 2441 alloc_large_system_hash("TCP established", 2442 sizeof(struct inet_ehash_bucket), 2443 thash_entries, 2444 (num_physpages >= 128 * 1024) ? 2445 13 : 15, 2446 0, 2447 &tcp_hashinfo.ehash_size, 2448 NULL, 2449 0); 2450 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; 2451 for (i = 0; i < tcp_hashinfo.ehash_size; i++) { 2452 rwlock_init(&tcp_hashinfo.ehash[i].lock); 2453 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain); 2454 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain); 2455 } 2456 2457 tcp_hashinfo.bhash = 2458 alloc_large_system_hash("TCP bind", 2459 sizeof(struct inet_bind_hashbucket), 2460 tcp_hashinfo.ehash_size, 2461 (num_physpages >= 128 * 1024) ? 2462 13 : 15, 2463 0, 2464 &tcp_hashinfo.bhash_size, 2465 NULL, 2466 64 * 1024); 2467 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; 2468 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 2469 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 2470 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 2471 } 2472 2473 /* Try to be a bit smarter and adjust defaults depending 2474 * on available memory. 2475 */ 2476 for (order = 0; ((1 << order) << PAGE_SHIFT) < 2477 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket)); 2478 order++) 2479 ; 2480 if (order >= 4) { 2481 tcp_death_row.sysctl_max_tw_buckets = 180000; 2482 sysctl_tcp_max_orphans = 4096 << (order - 4); 2483 sysctl_max_syn_backlog = 1024; 2484 } else if (order < 3) { 2485 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order); 2486 sysctl_tcp_max_orphans >>= (3 - order); 2487 sysctl_max_syn_backlog = 128; 2488 } 2489 2490 /* Set the pressure threshold to be a fraction of global memory that 2491 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of 2492 * memory, with a floor of 128 pages. 2493 */ 2494 limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); 2495 limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); 2496 limit = max(limit, 128UL); 2497 sysctl_tcp_mem[0] = limit / 4 * 3; 2498 sysctl_tcp_mem[1] = limit; 2499 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 2500 2501 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 2502 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); 2503 max_share = min(4UL*1024*1024, limit); 2504 2505 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM; 2506 sysctl_tcp_wmem[1] = 16*1024; 2507 sysctl_tcp_wmem[2] = max(64*1024, max_share); 2508 2509 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM; 2510 sysctl_tcp_rmem[1] = 87380; 2511 sysctl_tcp_rmem[2] = max(87380, max_share); 2512 2513 printk(KERN_INFO "TCP: Hash tables configured " 2514 "(established %d bind %d)\n", 2515 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size); 2516 2517 tcp_register_congestion_control(&tcp_reno); 2518 } 2519 2520 EXPORT_SYMBOL(tcp_close); 2521 EXPORT_SYMBOL(tcp_disconnect); 2522 EXPORT_SYMBOL(tcp_getsockopt); 2523 EXPORT_SYMBOL(tcp_ioctl); 2524 EXPORT_SYMBOL(tcp_poll); 2525 EXPORT_SYMBOL(tcp_read_sock); 2526 EXPORT_SYMBOL(tcp_recvmsg); 2527 EXPORT_SYMBOL(tcp_sendmsg); 2528 EXPORT_SYMBOL(tcp_sendpage); 2529 EXPORT_SYMBOL(tcp_setsockopt); 2530 EXPORT_SYMBOL(tcp_shutdown); 2531 EXPORT_SYMBOL(tcp_statistics); 2532